function K = randsig(m,n)
dims = repmat([m],[1 n]);

K = ones(m^n,1);


while 1
  sig = sign(randn(m,1));
  if ~all(sig==sig(1))
    break
  end
end

for xind = 1:m^n
  x = ind2coord(xind,dims);
  s = sig(x(1));
  K(xind) = K(xind)*s;
end

return